1. Field of the Invention
The present invention relates to a reel on which a recording tape, such as a magnetic tape or the like, is wound, and to a recording tape cartridge that accommodates, within a case, a reel on which a magnetic tape is wound.
2. Description of the Related Art
There are known tape reels in which the reel hub is formed in an hourglass shape in order to prevent a magnetic tape which is traveling from slipping in the transverse direction (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 8-297952). Further, there are known reels that have a winding core portion whose outer diameter is formed to be larger at the tape edge side which is the reference for the traveling of the magnetic tape, in order to make the PES (the standard deviation of the positional offsets) and the amount of off-track small (see, for example, JP-A No. 2002-245745). Moreover, a technique is known of providing a cylindrical-tube-shaped, metal insertion portion at a hub that is formed of resin and on which a magnetic tape is wound (see, for example, JP-A No. 2005-116163).
However, the magnetic tapes disclosed in JP-A Nos. 8-297952 and 2002-245745 do not take into consideration deformation of the hub due to the winding pressure of the magnetic tape. Further, although the magnetic tape disclosed in JP-A No. 2005-116163 takes suppressing of deformation of the hub into consideration, the shape of the hub after winding of the magnetic tape is not considered. The shape of the hub on which the magnetic tape is wound affects the curving (curvature) of the magnetic tape in the transverse direction.